1. Field of the Invention
The present invention relates to a tuning device for measuring and displaying a difference between a fundamental frequency of an instrumental sound or a musical sound signal and a reference frequency serving as a criterion for comparison.
2. Description of the Related Art
It has been generally known to remove a certain quantity of unnecessary components such as noise and harmonic components outside a range enabling the tuning of an instrument sound or a musical sound signal (i.e., a range from low pitch sounds to high pitch sounds) by means of a passive filter composed of a resistor and a capacitor, an active filter constructed of an operational amplifier, or the like, as disclosed in JP 9-6341 A (page, 4 FIG. 1).
A conventional tuning device is a fixed filter designed to remove noise and harmonic components outside a tuning-permitting range (i.e., a tonal range from low pitch sounds to high pitch sounds) and thus cannot exercise a filtering effect on unnecessary sounds within a range enabling the tuning of sounds other than those of an instrument to be tuned. As this phenomenon, it is possible to mention tuning in an environment surrounded by many instruments as in the case of, for example, a brass band. In such an environment, the tuning device is susceptible to the influence of ambient sounds and quite often makes an erroneous determination as a response to sounds of an instrument to be tuned.
Further, there is also a method of performing tuning by attaching a piezoelectric pickup to an instrument to avert the influence of ambient sounds and inputting an output signal from the piezoelectric pickup. However, the piezoelectric pickup may pick up not only the musical sounds to be tuned but also the sounds of other instruments in the neighborhood, including brass instruments resounding at high volume, as conductive noise. This constitutes a factor behind erroneous determinations made by the tuning device.
Still further, in the case of Taisho harps or in school lessons, there are often several performers lined up along a single desk to play instruments. In tuning the instruments in such situations, the above-mentioned conductive noise or vibrating sound causes erroneous determinations noticeably.